Step 1: Preheat your oven to 275°F (135°C). Line a large baking sheet with heavy-duty aluminum foil, ensuring enough overhang to create a tight seal later.
Step 2: Prepare the ribs by removing the silver skin (membrane) from the bone side of each rack. Use a knife to lift a corner of the membrane, then grab it with a paper towel and pull firmly to remove. Trim any excess fat if desired.
Step 3: In a small bowl, combine all dry rub ingredients: brown sugar, smoked paprika, garlic powder, onion powder, salt, black pepper, and cayenne (if using). Mix well.
Step 4: Generously apply the dry rub to both sides of the ribs, massaging it into the meat. Let the ribs sit at room temperature for at least 30 minutes, or refrigerate for 2-4 hours (or overnight) for deeper flavor.
Step 5: While the ribs are resting (or during the last 30 minutes), prepare the BBQ sauce. In a saucepan, combine all BBQ sauce ingredients: ketchup, apple cider vinegar, brown sugar, Worcestershire sauce, Dijon mustard, garlic powder, and smoked paprika. Bring to a simmer over medium heat, then reduce heat to low and cook for 10-15 minutes, stirring occasionally, until slightly thickened. Set aside.
Step 6: Place the seasoned ribs, meat-side up, on the prepared foil-lined baking sheet. Tightly cover the baking sheet with another layer of heavy-duty aluminum foil, crimping the edges securely to create a sealed packet. This ensures the ribs steam and tenderize perfectly.
Step 7: Bake in the preheated oven for 2.5 to 3.5 hours. Baby back ribs typically take 2.5-3 hours, while spareribs may need 3-3.5 hours. The ribs are done when they are very tender, and the meat has pulled back from the bone ends.
Step 8: Carefully remove the baking sheet from the oven. Uncover the ribs by removing the top layer of foil. Increase the oven temperature to 375°F (190°C). Carefully drain off any accumulated liquid from the foil packet.
Step 9: Brush both sides of the ribs generously with the prepared BBQ sauce. Return the uncovered ribs to the hotter oven and bake for another 20-30 minutes, or until the sauce is bubbly, caramelized, and sticky. For an extra thick glaze, baste with more sauce halfway through this step.
Step 10: For a slightly charred finish, you can carefully broil the ribs for 2-5 minutes, watching them constantly to prevent burning. This step is optional but adds a great texture.
Step 11: Remove the ribs from the oven and let them rest for 10-15 minutes before slicing between the bones. This allows the juices to redistribute, ensuring maximum tenderness. Serve immediately and enjoy your amazing Fall Off the Bone Oven Baked BBQ Ribs!